Apparatus for forming electrode of chip-like electronic part

ABSTRACT

An electrode is formed on a chip-like electronic part of the type having a central axis, a polygonal cross section as viewed in a plane which is perpendicular to the central axis, a plurality of side surfaces extending in respective planes which are generally parallel to the central axis, and a pair of end surfaces extending generally parallel to the central axis, each adjacent pair of side surfaces meeting along a respective edge of the chip-like electronic part. The electrode is formed by applying a first band of conductive material to at least one of the side surfaces and applying a second band of conductive material to the remaining side surface(s) in such a manner that the first and second bands meet at respective ones of the edges and together form a continuous band of conductive material extending around the outer periphery of the chip-type electronic part. The chip-like electronic part is held by a holder with a first plurality of side surfaces being exposed and facing a paste base on which a streak of conductive material is placed. The holder and paste base are brought together so that the first band of conductive material is applied to the first plurality of side surfaces. The chip-like electronic part is then repositioned with its remaining side surfaces being exposed and facing a paste base and the second band of conductive material is applied to those side surfaces.

CROSS-REFERENCE TO RELATED APPLICATION

This is a divisional of U.S. patent application Ser. No. 09/122,145,filed Jul. 24, 1998 now U.S. Pat. No. 6,270,613 in the name of TadahiroNakagawa et al. and entitled “PROCESS OF FORMING ELECTRODE OF CHIPELECTRONIC PART.”

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a process of forming an electrode for achip-like electronic part and a holder for a chip-like electronic part,particularly to a process of forming an electrode comprising aconductive paste on an outer surface of a chip-like electronic part anda holder for a chip-like electronic part preferably used in carrying outthe process.

2. Description of Related Art

FIG. 18 shows a perspective view of a chip-like electronic part 1,particularly a three terminal capacitor. End electrodes 2 and 3 areformed on respective end portions of the chip-like electronic part 1 andcentral electrodes 4 are formed at the central portion thereof.

Although not illustrated, first and second groups of inner electrodesare arranged alternately inside the chip-like electronic part 1 with theinner electrodes of the first group extending to the end electrodes 2and 3 and the inner electrodes of the second group extending to thecentral electrodes 4. Accordingly, electrostatic capacitances formedbetween the inner electrodes of the first group and the inner electrodesof the second group can be taken out between the end electrode 2 or 3and the central electrodes 4. The chip-like electronic part 1 is usedto, for example, remove noise on a signal line by coupling the endelectrodes 2 and 3 to the signal line and grounding the centralelectrodes 4.

As shown in FIG. 18, the central electrodes 4 extend across two opposingside faces of the chip-like electronic part 1. Because of limitationsassociated with the process commonly used to make the chip-likeelectronic part 1, the central electrodes 4 extend only partially on theother side faces of the chip-like electronic part. As a result, thecentral electrodes 4 do not extend entirely around the outer sidesurfaces of the chip-like electronic part 1.

The process for applying the central electrodes 4 is best understoodwith reference to FIG. 19. As shown herein, a groove 6 is provided in apaste base 5 which comprises an elastic body. The groove 6 is filledwith a conductive paste 7 to form an elongated streak 8 of conductivepaste 3. The chip-like electronic part 1 is held by a holder 9 so thatone face of the chip-like electronic part 1 faces the streak 8 ofconductive paste.

As best seen in FIG. 18, the chip-like electronic part 1 is an elongatedparallel-piped structure having a main axis extending from end electrode2 to end electrode 3. The central portion of the chip-like electronicpart 1 is aligned with the streak 8 of conductive paste with the axis ofthe streak extending perpendicular to the central axis of the chip-likeelectronic part 1. The chip-like electronic part 1 is brought intocontact with the paste base 5 and pressed against the paste base 5 todeform it and cause the conductive paste 7 to be applied to the outersurface of the chip-like electronic part 1 as shown by an imaginary linein FIG. 19. Although the conductive paste 7 extends across the entireside face of the chip-like electronic part 1 which faces the base 5, itonly extends partway up the adjacent side faces of the chip-likeelectronic part 1.

The orientation of the chip-like electronic part 1 is then reversed sothat its opposite face extends away from the holder and towards thepaste base 5 and the process is repeated to place the conductive paste 7on the opposite face (and particularly up the adjacent side faces) ofthe chip-like electronic part 1. Thereafter, the so applied centralelectrodes 4 are cured.

Instead of placing the conductive paste 7 in a groove 6 provided in theelastic paste base 5, the conductive paste may be applied (by printingor the like) on a flat face of a paste base 5 which can be eitherelastic or rigid. As another alternative, a reservoir of conductivepaste located on one side of a slit plate can be extruded to the otherside of the slit plate via the slit in the plate by applying pressure tothe conductive paste.

The end electrodes 2 and 3 are formed by dipping the ends of thechip-like electronic part 1 into a tank of conductive paste.

As mentioned above, the central electrode 4 does not normally extendaround the entire outer surface of the chip-like electronic part 1.However, it is preferable that it does to reduce unnecessary inductancecomponents where the central electrode is used as a ground electrode.

It is not impossible to form the central electrode to extend around theentire circumference of the chip-like electronic part 1 using theprocess shown in FIG. 19. This result can be achieved by providing asufficient amount of conductive paste to extend at least half way up thetwo side faces of the chip-like electronic part 1, for example, bymaking the groove deeper or pressing the chip-like electronic part 1more strongly against the paste base 5. However, as shown in thesectional view of FIG. 20, overlap portions 12 are formed on flat endfaces of the chip-like electronic part. These overlap portions 12 canhamper the mountability of the chip-like electronic part. Accordingly,it is preferable that a built-up portion, such as the overlap portion12, not be formed at the central portion of any of the side faces of thechip-like electronic part 1.

This can be avoided by using a small enough amount of conductive pastethat only one side of the chip-like electronic part receives the pasteduring any single application. However, this will necessitate fourseparate applications of the conductive paste which is not efficient.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a process of formingan electrode of a chip-like electronic part and a holder for a chip-likeelectronic part used in the process which can resolve the abovedescribed problem.

To this end, the process of the present invention forms an electrode ona chip-like electronic part of the type having a central axis, apolygonal cross section as viewed in a plane which is perpendicular tothe central axis, a plurality of side surfaces extending in respectiveplanes which are generally parallel to the central axis, and a pair ofend surfaces extending generally parallel to the central axis, eachadjacent pair of side surfaces meeting along a respective edge of thechip-like electronic part, the process comprising the steps of:

applying a first band of conductive material to at least one of the sidesurfaces; and

applying a second band of conductive material to the remaining sidesurface(s) in such a manner that the first and second bands meet atrespective ones of the edges and together form a continuous band ofconductive material extending around the outer periphery of thechip-type electronic part.

In the preferred embodiment, the first and second bands are applied tothe side surfaces at an area that lies between the end surfaces, andmore preferably in the middle, of the chip-like electronic part and donot extend to either end surface.

In the preferred embodiment, the chip-like electronic part has four sidesurfaces, the first band is applied to first and second contiguous sidesurfaces and the second band is applied to third and fourth contiguousside surfaces by bringing the side surfaces into contact with strips ofconductive paste. The chip-like electronic part is first held in aholder with the first and second side surfaces extending outwardly fromthe holder and the first band is applied to the first and second sidesurfaces by moving a strip of conductive paste located on an elasticpaste base into contact with the first and second side surfaces.Thereafter, the orientation of the chip-like electronic part is changedby either moving it within the same holder or moving it to a secondholder to ensure that the third and fourth side surfaces extendoutwardly from the holder. Once in this position, the second band isapplied to the third and fourth side surfaces by moving a strip ofconductive paste located on an elastic paste base into contact with thethird and fourth side surfaces.

When desired, the first and second bands can be applied to the sidesurfaces at an area of the side surfaces located adjacent one of the endsurfaces thereof and can simultaneously be applied to the adjacent oneof the end surfaces as well as the side surfaces.

The process of the present invention can also be used to place aplurality of electrodes on a chip-like electronic part having a centralaxis, a polygonal cross section as viewed in a plane which isperpendicular to the central axis, a plurality of side surfacesextending in respective planes which are generally parallel to thecentral axis, and a pair of end surfaces extending generally parallel tothe central axis, each adjacent pair of side surfaces meeting along arespective edge of the chip-like electronic part. In such a case, theprocess preferably comprising the steps of:

applying a set of first bands of conductive material to at least one ofthe side surfaces, each of the first bands being applied at a differentaxial position on the side surfaces so as to be spaced from one another;and

applying a set of second bands of conductive material to the remainingside surface(s), each of the second bands being applied at a differentaxial position of the remaining side surfaces so as to be spaced fromone another, each band of the first set meeting a respective band of thefirst set at two respective edges such that each respective pair ofbands forms a continuous band of conductive material extending aroundthe outer periphery of the chip-type electronic part. More preferably,the chip-like electronic part has four side surfaces and is in the formof a quadrangular prism.

In the preferred embodiment, three continuous bands are formed, twoadjacent the end surfaces of the chip-like electronic part, the third ata position intermediate the two end surfaces of the chip-like electronicpart. The bands of conductive material are applied to the side surfacesby bringing them into contact with strips of conductive paste. In thepreferred embodiment, the first applying step is carried out by holdingthe chip-type electronic part in a holder with the first and second sidesurfaces extending outwardly from the holder and the first set of bandsare applied to the first and second side surfaces by moving a pluralityof strips of conductive paste located on an elastic paste base intocontact with the first and second side surfaces. Similarly, the secondapplying step is carried out by holding the chip-type electronic part ina holder with the third and fourth side surfaces extending outwardlyfrom the holder and the second set of bands is applied to the third andfourth side surfaces by moving a plurality of strips of conductive pastelocated on an elastic paste base into contact with the third and fourthside surfaces. The same or different holders can be used for the firstand second applying steps.

According to a further aspect of the process of the present invention,an electrode is formed on each of a plurality of chip-like electronicparts of the type having a central axis, a polygonal cross section asviewed in a plane which is perpendicular to the central axis, aplurality of side surfaces extending in respective planes which aregenerally parallel to the central axis, and a pair of end surfacesextending generally parallel to the central axis, each adjacent pair ofside surfaces meeting along a respective edge of the chip-likeelectronic part, and the process comprises the steps of:

simultaneously applying a first band of conductive material to at leastone of the side surfaces of each of the chip-like electronic parts; and

simultaneously applying a second band of conductive material to theremaining side surface(s) of each of the chip-like electronic parts insuch a manner that the first and second bands of a respective chip-likeelectronic part meet at respective ones of the edges on that chip-likeelectronic part and together form a continuous band of conductivematerial extending around the outer periphery of that chip-typeelectronic part.

In the preferred embodiment, each of the chip-like electronic parts hasfour side surfaces and each of the first bands is applied to first andsecond contiguous side surfaces and wherein each of the second bands isapplied to the remaining two side surfaces by bringing the side surfacesinto contact with strips of conductive paste. The first applying step iscarried out by holding each of the chip-type electronic parts in asingle holder with the first and second side surfaces of each chip-likeelectronic part extending outwardly from the holder and the first bandis applied to the first and second side surfaces of each of thechip-like electronic parts by moving respective strips of conductivepaste located on an elastic paste base into contact with the first andsecond side surfaces. The second applying step is carried out by holdingeach of the chip-type electronic parts in a single holder with the thirdand fourth side surfaces extending outwardly from the holder and thesecond band is applied to the third and fourth side surfaces by movingstrips of conductive paste located on an elastic paste base into contactwith the third and fourth side surfaces. Again, a single or multipleholders can be used.

The present invention is also directed toward a combination, comprising:

a chip-like electronic part having a plurality of outer surfacesextending generally parallel to a central axis of the chip-likeelectronic part, at least one of the surfaces having a band ofconductive material located thereon; and

a holder holding the chip-like conductive part in an orientation whereinat least one of the outer surfaces of the chip-like electronic partextends outwardly from the holder and wherein the surface(s) of thechip-like electronic part which have the band of conductive materiallocated thereon face inwardly of the holder and are not exposed.

In the preferred embodiment, the holder includes a recess in which theband of conductive material is located without the conductive materialtouching the walls of the recess. The holder has a groove, including aplurality of side walls, for holding the electronic part, the shape ofthe groove corresponding generally to the shape of the portion of thechip-like electronic part being held in the groove. The walls of thechip-like electronic part which have the band of conductive materialformed thereon are preferably in contact with the side walls of thegroove and the band of conductive material itself is situated in arecess formed in the groove such that the band of conductive materialdoes not contact the walls of the groove or the walls of the recess.When the chip-like electronic part is formed in a shape of aquadrangular prism, the groove is formed in a V-like shape.

The present invention is also directed towards a chip-like electronicpart comprising:

a main body portion having a central axis, a polygonal cross section asviewed in a plane which is perpendicular to the central axis, aplurality of side surfaces extending in respective planes which aregenerally parallel to the central axis, and a pair of end surfacesextending generally parallel to the central axis, each adjacent pair ofside surfaces meeting along a respective edge of the main body portion;

a pair of end electrodes located on the end surfaces of the main bodyportion; and

a central electrode comprising a sintered metal formed of an electrodepaste and extending over each of the side surfaces of the main bodyportion so as to extend entirely around the outer periphery of the mainbody portion, the central electrode being formed of two bands ofsintered conductive paste, the two bands meeting at respective edges ofthe main body portion.

The two respective edges are preferably located 180 degrees apart fromone another as measured around the central axis of the main body portionwith the two bands overlapping one another at the respective edges.

BRIEF DESCRIPTION OF THE DRAWINGS

For the purpose of illustrating the invention, there is shown in thedrawing a form which is presently preferred, it being understood,however, that the invention is not limited to the precise arrangementand instrumentality shown.

FIG. 1 is a perspective view of a chip-like electronic part 21 to whicha process of forming an electrode according to one embodiment of thepresent invention is applied.

FIG. 2 is a sectional view showing an inner electrode 25 of thechip-like electronic part 21 of FIG. 1;

FIG. 3 is a sectional view showing an inner electrode 26 of thechip-like electronic part 21 of FIG. 1.

FIG. 4 is a perspective view of a chip-like electronic part 21 a towhich a process of forming an electrode according to other embodiment ofthe present invention is applied.

FIG. 5 is a front view showing a plurality of chip-like electronic parts21 of FIG. 1 held by a holder 27.

FIG. 6 is a partial, enlarged front view showing a single chip-likeelectronic part 21 held by the holder 27 of FIG. 5.

FIG. 7 is a side view showing a single chip-like electronic part beingheld by the holder 27 of FIG. 5 and also showing a section of paste base39.

FIG. 8 is a view corresponding to FIG. 7 but in which a paste base 43 isused in place of the paste base 39 of FIG. 7.

FIG. 9 is a view corresponding to FIG. 7 in which a slit plate 45 isused in place of the paste base 39 of FIG. 7.

FIG. 10 a bottom view showing a portion of a holder 27 a which ispreferably used in a step of providing a conductive paste 41 at a secondtime.

FIG. 11 is a bottom view showing the chip-like electronic part 21 beingheld by the holder 27 a of FIG. 10.

FIG. 12 is a sectional view taken along a line XII—XII of FIG. 11.

FIG. 13 is a sectional view schematically showing the chip-likeelectronic part 21 provided with conductive pastes 41 a and 41 b for thecentral electrode 4 of FIG. 1.

FIG. 14 is a view corresponding to FIG. 6 showing the chip-likeelectronic part 21 a of FIG. 4 being held by a holder 27 b.

FIG. 15 is a view corresponding to FIG. 8 for explaining anotherembodiment of the present invention.

FIG. 16A is a perspective view showing the chip-like electronic part 21after the conductive paste 41 has been applied to one-half of theelectronic part after having been processed by the step shown in FIG.15.

FIG. 16B is a perspective view showing the chip-like electronic part 21after the conductive paste 41 has been applied to all of the electronicpart.

FIG. 17 is a sectional view for explaining a further embodiment of thepresent invention and showing the chip-like electronic part 21 beingheld by a holder 27 c which is used in place of the holder 27 shown byFIG. 5 through FIG. 7.

FIG. 18 is a perspective view of a conventional chip-like electronicpart 1 which is of interest for the present invention.

FIG. 19 is a view corresponding to FIG. 7 showing a step of providing aconductive paste 7 onto the chip-like electronic part 1 to form acentral electrode 4.

FIG. 20 is a sectional view schematically showing the conductive paste 7extending along the entry periphery of the outer surface of thechip-like electronic part 1 using the process shown in FIG. 19.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings wherein like numerals indicate likeelements, there is shown in FIG. 1 a chip-like electronic part 21 onwhich a central electrode has been formed using a process correspondingto a first embodiment of the present invention. The chip-like electronicpart 21 is a quadrangular prism having a section which is substantiallysquare in shape. End electrodes 22 and 23 are respectively formed onopposite end surfaces of the chip-like electronic part 21 and a centralelectrode 24 is formed at the central portion thereof (as measured alongthe central axis of the part 21). The central electrode 24 is formed toextend around the entire periphery of the outer surface of the chip-likeelectronic part 21.

The chip-like electronic part 21 constitutes a three terminal capacitorhaving at least one, and preferably a plurality, of inner electrodes 25defining a first group of inner electrodes (one of which is shown inFIG. 2) and at least one, and preferably a plurality, of innerelectrodes 26 defining, a second group of inner electrodes (one of whichis shown in FIG. 3). Individual electrodes of the first and secondgroups are arranged alternately to one another so as to be interleaved.As shown in FIG. 2, the inner electrodes 25 of the first group arecoupled to the end electrodes 22 and 23. As shown in FIG. 3, the innerelectrodes 26 of the second group are coupled to the central electrode24. The electrostatic capacitances formed between the inner electrodes25 of the first group and the inner electrodes 26 of the second groupcan be taken out between the end electrode 22 or 23 and the centralelectrode 24. The chip-like electronic part 21 can be used, for example,to remove noise on a signal line by interposing the end electrodes 22and 23 in the signal line and grounding the central electrode 24.

The process of the present invention can also be used to apply thecentral electrode to the chip-like electronic part 21 a of FIG. 4.Chip-like electronic part 21 a is substantially similar to chip-likeelectronic part 21 of FIG. 1 except that it has a rectangular crosssection. Since the structure is otherwise the same, no furtherdescription is provided.

An explanation will be provided of a process of forming the centralelectrode 24 of the chip-like electronic part 21 shown by FIG. 1 withreference to FIG. 5 through FIG. 13. Because the end electrodes 22 and23 are normally formed after the central electrode 24 is formed in FIG.5 through FIG. 9 and FIG. 11 through FIG. 13, the end electrodes 22 and23 of the chip-like electronic part 21 are not illustrated. However,this is not necessarily the case and the central electrode 24 may beapplied after the end electrodes 22 and 23 have already been formed.

Referring to FIG. 5, a holder 27 adapted to hold a plurality of thechip-like electronic parts is attached to a rigid base. An enlarged viewof a portion of the holder 27 is shown in FIG. 6.

The holder has a plurality of holding portions 33 for holding aplurality of the chip-like electronic parts 21. Each chip-likeelectronic part 21 has at least two outer surfaces facing outward sothat a portion of the central electrode can be applied thereto. Moregenerally, a portion of the outer surface corresponding to an arc of atleast 180° around the center axis of the part 21 is exposed. In theexample shown, two side faces 31 and 32, located on opposite sides ofedge line 30, are exposed. Each of the holding portions 33 is preferablyprovided with a holding groove 34 for receiving the non-exposed surfacesof the chip-like electronic part 21. The holding groove 34 has a contactface 35 against which the non-exposed surfaces 37 and 38 of thechip-like electronic part 21 rest. Since the chip-like electronic part21 has a square cross-section the contact face 35 has a V-like shape.

The holder 27 is formed, for example, from an elastic body. The contactface 35 adheres to the chip-like electronic part 21 to hold it in place.This can be achieved by any suitable means such as by vacuum sucking.

Next, as shown in FIG. 7, a groove 40 located in an elastic paste base39 is filled with a conductive paste 41 to form a paste streak 42 (pasteextending in a shape of a streak). The chip-like electronic part 21 isheld by the holder 27 in an orientation wherein the paste streak 42extends orthogonal to the central axis of the chip-like electronic part21 and is positioned at a location corresponding to the middle of thechip-like electronic part 21. The holder 27 and the paste base 39 arebrought into contact with one another so that the paste base 39 isdeformed and presses against the outer side surfaces 31, 32 of thechip-like electronic part 21 and conductive paste 41 from the pastestreak 42 is applied to the side surfaces 31, 32 as shown in phantom inFIG. 7.

In accordance with this step of the process, a band of conductive paste41 is provided on the contiguous side faces 31 and 32 but is not appliedto the opposite side faces 37 and 28. Similarly, the conductive pastedoes not stain the holder 27. The resultant band of conductive paste 41is shown in FIG. 13 as band 41 a.

Two non-limiting alternative process of forming the conductive pastestreak 42 are shown in FIGS. 8 and 9.

In the embodiment of FIG. 8, the conductive paste 41 is applied to theflat face of the paste base 43 which may be an elastic or rigid body. Ifit is a rigid body, it may be necessary to rotate the part 21 back andforth about its longitudinal axis to bring the two opposite side faces31 and 32 into contact with the paste streak 42. The conductive paste 41may be built up onto the surface of the paste base 43 by printing or thelike to form a conductive paste streak 42.

In the embodiment of FIG. 9, a supply of conductive paste 41 is arrangedon one side of a plate 45 having an elongated slit 44 (which may berigid or deformable) and is extruded through the slit 44 to form aconductive paste streak 42.

The paste base 39 of FIG. 7 and the paste base 43 of FIG. 8 arepreferably deformed more easily than the elastic body constituting theholder 27 to avoid undesirable deformation of the holder 27.

Once the conductive paste 41 has been applied to the faces 31, 32 of thechip-like electronic part 21, the part 21 is either transferred to asecond holder or removed from the first holder, rotated, and returnedthereto, for application of conductive paste to the remaining two sidefaces 37 and 38. The second holder may have a structure similar oridentical to that of the holder 27. In any event, the chip-likeelectronic part 21 is held by the holder so that the coated sidesurfaces 31, 32 face inwardly (are not exposed) and the remaining faces37, 38 face outwardly as shown in FIG. 12. In the preferred embodiment,two substantially similar holders are used and the transfer takes placeby positioning the two holders opposite one another and simultaneouslytransferring the plurality of the chip-like electronic parts 21 from thefirst holder to the second holder in a single motion.

In the case where the second holder is used as described above, it ispreferable to use a holder 27 a shown in FIG. 10 through FIG. 12. Holder27 a is provided with a recess portion 46 which accommodates the band ofconductive paste 41 applied to the side surfaces 31, 32 and prevents theholder 27 a from being brought into contact with the conductive paste 41on these sides. This prevents the band of conductive paste 41 from beingpeeled off and the holder 27 a from being stained by the conductivepaste 41. The width of the recess portion 46 is preferably wider thanthat of the band of conductive paste 41. The structure of the holder 27a is otherwise substantially similar to that of the holder 27 and afurther explanation will not be provided. This holder may be used withany of the foregoing paste bases, for example, that of FIG. 7.

As shown in FIGS. 11 and 12, the holder 27 a holds the chip-likeelectronic part 21 with the uncoated side surfaces 37, 38 facingoutwardly and with the band of conductive paste 41 located on sidesurfaces 31, 32 positioned inside of the recess portion 46. Theconductive paste 41 is then applied to the exposed side surfaces 37, 38in accordance with any of the process described above. When this processis completed, the band of conductive paste 41 will extend around theentire periphery of the chip-like electronic part as illustrated in FIG.13 without the formation of build up (e.g. overlap) areas in the centralportions of the side faces 31, 32, 37 and 38 such as are created whenusing the prior art processes. Compare FIGS. 13 and 20. By curing theconductive pastes 41 a and 41 b, the desired central electrode 24 asshown by FIG. 1 is formed.

To form the end electrodes 22 and 23 at respective end portions of thechip-like electronic part 21, the end portion of the chip-likeelectronic part 21 may be dipped into a tank of conductive paste andthereafter, the conductive paste is cured. It is preferable that thecuring operation be carried out simultaneously with the curing operationfor forming the central electrode 24 mentioned above.

When forming the central electrode 24 on a chip-like electronic part 21b having a rectangular cross section, a holder 27 b (FIG. 14) is used.This holder has a holding groove 34 b whose shape corresponds to that ofthe chip-like electronic part 21 b. More particularly, the holdinggroove 34 b has the shaped right triangle dividing the cross sectionalprofile of the chip-like electronic part 21 a diagonally. The structureand operation of holder 27 b is otherwise the same as holder 27 and nofurther description will be provided.

In the foregoing embodiments, the end electrodes 22, 23 are preferablyformed by dipping. However, they can also be formed by, for example,using a process similar to that used to form central electrode 24 asshown in FIGS. 15 and 16.

As shown in FIG. 15, three conductive paste streaks 42 a, 42 b and 42 care formed on an elastic paste base 43 at areas corresponding to thecentral portion and end portions of the chip-like electronic part 21. Inthe embodiment shown, the conductive paste streaks 42 a, 42 b and 42 c,are placed on a flat surface of the paste base 43. Other processes suchas that of FIGS. 7 and 9 can also be used. Whichever process is used,the holder 27 and paste base 43 are moved toward one another to bringthe conductive paste streaks 42 a, 42 b and 42 c into contract with theside surfaces 31, 32 of the chip-like electronic part 21 while the pastebase 43 is deformed to surround those side surfaces. As a result, asshown in FIG. 16A, band of conductive paste 41 is applied to the outersurfaces 31, 32 as well as one half of the end surfaces of the chip-likeelectronic part 21.

The chip-like electronic part 21 is then held in an orientation whereinthe two uncoated side faces 37 and 38 are exposed and a coating ofconductive paste 41 is applied to the side surfaces 37, 38 as well asthe remaining end surfaces using the foregoing process to form threebands of conductive paste 41 extending around the entire periphery ofthe part 21 and corresponding to a central electrode 24 and two endelectrodes 22 and 23.

As shown in FIG. 16B, the conductive paste 41 is applied to all areaswhere end electrodes 22 and 23 and the central electrode 24 should beformed. Overlapping portions X are formed in the end electrodes 22, 23and the central electrode 24 as a result of the conductive paste 41being applied as described above. Finally, the conductive paste 41 iscured, thereby forming the end electrodes 22, 23 and the centralelectrode 24. The overlapping portions X of the conductive paste areswollen after the conductive paste 41 as has been cured.

If desired, the foregoing process may be used to form just the endelectrodes 22, 23 of the chip-like electronic part 21 in which case onlythe conductive paste streaks 42 b and 42 c (FIG. 15) are formed on thepaste base.

In lieu of the foregoing holders which contain a holding groove, theholder 27 c of FIG. 17 may be used (indeed any suitable holder may beused to carry out the process of the present invention). Holder 27 c hasa holding hole 47 for holding the chip-like electronic part in therequired orientation. At least an inner peripheral face portion 48 ofthe holding hole 47 is elastic. The chip-like electronic part 21 is heldin a desired orientation by elastically sandwiching opposite end facesof the chip-like electronic part 21 extending perpendicular to the hole47.

In the foregoing embodiments, the process of the present invention isapplied to a chip-like electronic part 21 or 21 a in the shape of aquadrangular prism. However, the process of the present invention can beused with other chip-like electronic parts such as those having apolygonal or a cylindrical shape. In the case of the chip-likeelectronic part having a cylindrical shape, one of generators present onthe outer surface constitutes one edge line. Additionally, the presentinvention is applicable to a chip-like electronic part other than thethree terminal capacitor.

The present invention may be embodied in other specific forms withoutdeparting from the spirit or essential attributes thereof and,accordingly, reference should be made to the appended claims, ratherthan to the foregoing specification, as indicating the scope of theinvention.

What is claimed is:
 1. A combination, comprising: a chip electronic parthaving a plurality of outer surfaces extending generally parallel to acentral axis of the chip electronic part, at least one of the outersurfaces having a band of conductive material located thereon; and aholder holding the chip conductive part in an orientation wherein atleast one of the outer surfaces of the chip electronic part extendsoutwardly from the holder and wherein the surface(s) of the chipelectronic part which have the band of conductive material locatedthereon face inwardly of the holder and are not exposed.
 2. Thecombination of claim 1, wherein the holder includes a recess in whichthe band of conductive material is located.
 3. The combination of claim1, wherein the holder has a groove, including a plurality of side walls,for holding the electronic part, a shape of the groove correspondinggenerally to the shape of the portion of the chip electronic part beingheld in the groove, at least a portion of the band of conductivematerial being located in the groove.
 4. The combination of claim 3,wherein the walls of the chip electronic part which have the band ofconductive material formed thereon are in contact with the side walls ofthe groove and the band of conductive material itself is situated in arecess formed in the groove such that the band of conductive materialdoes not contact the walls of the groove or the walls of the recess. 5.The combination of claim 3, wherein the chip electronic part is formedin a shape of a quadrangular prism and the groove is formed in a V-likeshape.
 6. A chip electronic part comprising: a main body portion havinga central axis, a polygonal cross section as viewed in a plane which isperpendicular to the central axis, a plurality of side surfacesextending in respective planes which are generally parallel to thecentral axis, and a pair of end surfaces extending generally parallel tothe central axis, each adjacent pair of side surfaces meeting along arespective edge of the main body portion; a pair of end electrodeslocated on the end surfaces of the main body portion; and a centralelectrode comprising a sintered metal formed of an electrode paste andextending over each of the side surfaces of the main body portion so asto extend entirely around the outer periphery of the main body portion,the central electrode being formed of two bands of sintered conductivepaste, the two bands meeting at respective edges of the main bodyportion.
 7. The chip electronic part of claim 6, wherein the tworespective edges are located 180 degrees apart from one another asmeasured around the central axis of the main body portion.
 8. The chipelectronic part of claim 7, wherein the two bands overlap one another atthe respective edges.
 9. The combination of claim 2, wherein the holderholds the chip electronic part in the recess without the band ofconductive material touching the walls of the recess.
 10. The chipelectronic part of claim 6, wherein a build up area is not formed in thecentral portion of the side surfaces.